[PATCH 2/2] drm/i915: Fix a memory leak with reused mmap_offset

[Nirmoy Das]

drm_vma_node_allow() and drm_vma_node_revoke() should be called in
balanced pairs. We call drm_vma_node_allow() once per-file everytime a
user calls mmap_offset, but only call drm_vma_node_revoke once per-file
on each mmap_offset. As the mmap_offset is reused by the client, the
per-file vm_count may remain non-zero and the rbtree leaked.

Call drm_vma_node_allow_once() instead to prevent that memory leak.

Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
Cc: Andi Shyti <andi.shyti at linux.intel.com>

Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_mman.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index 4f69bff63068..2aac6bf78740 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -697,7 +697,7 @@ mmap_offset_attach(struct drm_i915_gem_object *obj,
 	GEM_BUG_ON(lookup_mmo(obj, mmap_type) != mmo);
 out:
 	if (file)
-		drm_vma_node_allow(&mmo->vma_node, file);
+		drm_vma_node_allow_once(&mmo->vma_node, file);
 	return mmo;
 
 err:
-- 
2.39.0